Vehicle position adjustment type steering column device

ABSTRACT

An apparatus comprises a vehicle body side bracket  4  having a vehicle body mount portion  4   c  to be mounted on a vehicle body and paired left and right opposed flat plate portions  4   a,    4   b,  a steering column  2  having an expanded portion  13,  formed by expanding a portion of a tubular material, that is to be in pressure contact with the pair of opposed flat plate portions  4   a,    4   b  of the vehicle body side bracket;  
     a shaft  5  inserted through the pair of opposed flat plate portions  4   a,    4   b  and the expanded portion  13  and adapted to adjust the distance between the pair of opposed flat plate portions  4   a,    4   b  as an operation lever  8  is rotated. The steering column  2  has a portion that is present in an area extending from the shaft  5  up to at least the vehicle body mount portion  4   c  and has a width substantially equal to the width of a penetrated portion of the expanded portion  13  at which the shaft  5  is inserted through.

TECHNICAL FIELD

The present invention relates to a position adjustable steering columnapparatus for a vehicle that has an expanded portion formed by expandinga portion of a tubular material of a steering column.

BACKGROUND ART

In general, the steering apparatus for a vehicle is equipped with a tiltmechanism for changing the position of the steering column up and downso that the steering wheel will be adjusted to a position suitable forthe driver. This tilt mechanism is provided with a lever-operated clampmechanism. In the tilting operation, the clamp can be loosened byoperating the lever so as to allow free movement of the steering column,and the clamp can be tightened after the position has been adjusted tomaintain the constrained state of the steering column.

Specifically, as shown in FIG. 13, a steering apparatus is provided witha steering column 2 for supporting a steering shaft 1 along the axis bymeans of a bearing (not shown) and a clamp mechanism 3. The clampmechanism 3 comprises a tilt bracket 4, a tilt bolt 5, a nut 6, adistance bracket 7, a tilt lever 8 and paired fixed and movable cams 9and 10.

For example, as the movable cam 10 is rotated by a rotation of the tiltlever 8, the movable cam is shifted relative to the fixed cam 9. Thiscauses a relative shift of the tilt bolt 5 in the axial direction. Bythis process, the distance bracket 7 is held between support portions 4a and 4 b of the tilt bracket 4, so that the steering column 2 can befixed. On the other hand, as the tilt lever 8 is operated in the reversedirection, the tilt bolt 5 is shifted in the reverse direction. By thisprocess, the clamping of the steering column 2 is released, and thesteering column 2 can be tilted to a desired angle.

Both side walls of the distance bracket 7 are sometimes designed toextend to a position beyond the center of the steering column 2 in orderto compensate lack of rigidity in supporting the steering column 2, forexample as shown in FIG. 14. Another countermeasure proposed for thesame purpose is to dispose a spacer 11 made of a resin between thesupport portions 4 a and 4 b of the tilt bracket 4 as shown in FIG. 15.

However, even though the intended object is attained by both theabove-described methods, one of the methods in which both the side wallsof the distance bracket 7 are extended is not preferable, since theincrease in the size of the distance bracket 7 results in an increase inthe weight. On the other hand, in the method of providing the spacer 11,an increase in the number of the parts constituting the clamp mechanismis inevitable. This entails a significant increase in the cost, and thismethod is not preferable either.

In view of the above, an object of the present invention is to provide aposition adjustable steering column apparatus for a vehicle in whichrigidity of supporting is improved without adding a special member forsupporting the steering column.

SUMMARY OF THE INVENTION

In order to attain the above object, a position adjustable steeringapparatus for a vehicle according to a first aspect of the presentinvention comprises:

a vehicle body side bracket having a vehicle body mount portion to bemounted on a vehicle body and paired left and right opposed flat plateportions extending in the substantially vertical direction;

a steering column for rotatably supporting a steering shaft, thesteering column having an expanded portion, formed by expanding aportion of a tubular material, that is to be in pressure contact withthe pair of opposed flat plate portions of said vehicle body sidebracket;

a shaft inserted through said pair of opposed flat plate portions andsaid expanded portion; and

an adjustment mechanism that acts on said shaft as an operation lever isrotated, for adjusting the distance between said pair of opposed flatplate portions,

wherein said steering column has a portion that is present in an areaextending from said shaft up to at least said vehicle body mount portionand has a width substantially equal to the width of a penetrated portionof said expanded portion at which said shaft is inserted through.

A position adjustable steering apparatus for a vehicle according to asecond aspect of the present invention comprises:

a vehicle body side bracket having a vehicle body mount portion to bemounted on a vehicle body and paired left and right opposed flat plateportions extending in the substantially vertical direction;

a steering column for rotatably supporting a steering shaft, thesteering column having an expanded portion, formed by expanding aportion of a tubular material, that is to be in pressure contact withthe pair of opposed flat plate portions of said vehicle body sidebracket;

a shaft inserted through said pair of opposed flat plate portions andsaid expanded portion; and

an adjustment mechanism that acts on said shaft as an operation lever isrotated, for adjusting the distance between said pair of opposed flatplate portions,

wherein said steering column has a portion that is present in an areaextending from said shaft up to at least said vehicle body mount portionand has a width larger than the width of a penetrated portion of saidexpanded portion at which said shaft is inserted through.

A position adjustable steering apparatus for a vehicle according to athird aspect of the present invention comprises:

a vehicle body side bracket having a vehicle body mount portion to bemounted on a vehicle body and paired left and right opposed flat plateportions extending in the substantially vertical direction;

a steering column for rotatably supporting a steering shaft, thesteering column having a first expanded portion, formed by expanding aportion of a tubular material, that is to be in pressure contact withthe pair of opposed flat plate portions of said vehicle body sidebracket;

a shaft inserted through said pair of opposed flat plate portions andsaid first expanded portion; and

an adjustment mechanism that acts on said shaft as an operation lever isrotated, for adjusting the distance between said pair of opposed flatplate portions,

wherein said steering column has a second expanded portion expanded froma substantially center portion thereof at said vehicle body mountportion side, and

said steering column has a portion that is present in an area extendingfrom said shaft up to at least said vehicle body mount portion and has awidth substantially equal to the width of a penetrated portion of saidfirst expanded portion at which said shaft is inserted through and thewidth of said second expanded portion.

A position adjustable steering apparatus for a vehicle according to afourth aspect of the present invention comprises:

a vehicle body side bracket having a vehicle body mount portion to bemounted on a vehicle body and paired left and right opposed flat plateportions extending in the substantially vertical direction;

a steering column for rotatably supporting a steering shaft, thesteering column having a first expanded portion, formed by expanding aportion of a tubular material, that is to be in pressure contact withthe pair of opposed flat plate portions of said vehicle body sidebracket;

a shaft inserted through said pair of opposed flat plate portions andsaid first expanded portion; and

an adjustment mechanism that acts on said shaft as an operation lever isrotated, for adjusting the distance between said pair of opposed flatplate portions,

wherein said steering column has a second expanded portion expanded froma substantially center portion thereof at said vehicle body mountportion side, and

said steering column has a portion that is present in an area extendingfrom said shaft up to at least said vehicle body mount portion and has awidth larger than the width of a penetrated portion of said firstexpanded portion at which said shaft is inserted through and the widthof said second expanded portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side view of a tilting steering apparatus for a vehicleaccording to a first embodiment of the present invention; FIG. 1B is across sectional view taken along line b-b in FIG. 1A.

FIGS. 2A to 2C show portions of interest of a steering column shown inFIGS. 1A and 1B; FIG. 2A is a perspective view of the steering column;FIG. 2B is a side view of the steering column; and FIG. 2C is a crosssectional view of the steering column.

FIGS. 3A and 3B show a steering column according to a second embodimentof the present invention; FIG. 3A is a side view of the steering column;and FIG. 3B is a cross sectional view of the steering column.

FIGS. 4A and 4B show a steering column according to a third embodimentof the present invention; FIG. 4A is a side view of the steering column;and FIG. 4B is a cross sectional view of the steering column.

FIGS. 5A and 5B show a steering column according to a fourth embodimentof the present invention; FIG. 5A is a side view of the steering column;and FIG. 5B is a cross sectional view of the steering column.

FIGS. 6A and 6B show a modification of the steering column according tothe fourth embodiment of the present invention; FIG. 6A is a side viewof the steering column; and FIG. 6B is a cross sectional view of thesteering column.

FIG. 7 is a side view showing a tilting telescopic steering apparatusaccording to a fifth embodiment of the present invention as a whole.

FIG. 8 is a cross sectional view taken along line A-A in FIG. 7 showingonly an expanded portion of the steering column.

FIG. 9A is a cross sectional view taken along line A-A in FIG. 7 showinga state in which clamping of the column is released; and FIG. 9B is asimilar cross sectional view showing a state in which the column isclamped.

FIG. 10A is an enlarged side view showing a portion of interest of thesteering column of a tilting steering apparatus for a vehicle accordingto a sixth embodiment of the present invention; and FIG. 10B is a crosssectional view taken along line b-b in FIG. 10A.

FIG. 11 is a transverse cross sectional view of a tilting steeringapparatus for a vehicle according to a seventh embodiment of the presentinvention.

FIG. 12A is an enlarged side view showing a portion of interest of thesteering column of a tilting steering apparatus for a vehicle accordingto the seventh embodiment of the present invention; and FIG. 12B is across sectional view taken along line b-b in FIG. 12A.

FIG. 13 is a cross sectional view showing a conventional steering columnapparatus.

FIG. 14 is a cross sectional view showing another conventional steeringcolumn apparatus.

FIG. 15 is a cross sectional view showing a still other conventionalsteering column apparatus.

EMBODIMENTS OF THE INVENTION First Embodiment Tilting Type

The first embodiment of the present invention will be described withreference to drawings.

FIG. 1A is a side view showing a tilting steering apparatus for avehicle according to the first embodiment of the present invention. FIG.1B is a cross sectional view taken along line b-b in FIG. 1A.

In FIGS. 2A to 2C that show portions of interest of the steering columnshown in FIGS. 1A and 1B, FIG. 2A is a perspective view of the steeringcolumn, FIG. 2B is a side view of the steering column, and FIG. 2C is across sectional view of the steering column.

As shown in FIG. 1A, in the interior of the steering column 2, asteering shaft 1 having a steering wheel 100 on its top is rotatablysupported. The steering shaft 1 is supported on the steering column 2 bymeans of a rear side (with respect to the vehicle body) bearing 101 anda front side bearing 102.

The steering column 2 is attached to the vehicle body at its lower endportion by means of a vehicle body side lower bracket 103, and at itsmid portion by means of a vehicle body side upper bracket 4 (or a tiltbracket) which is substantially L-shaped as seen from the side.

Inside the vehicle body side lower bracket 103 having a substantiallyU-shape, a column side lower bracket 104 is held. The column side lowerbracket 104 may be formed integrally with the steering column 2 by ahydraulic bulge forming process, which will be described later, oralternatively it may be attached to the steering column 2 by welding.

On the vehicle body side lower bracket 103, a cut-away portion 105 thatopens to the front side of the vehicle body is formed. A tilt centerbolt 106 inserted through the column side lower bracket 104 is designedto engage the notch 105. With this structure, when a secondary collisionoccurs, the steering column 2 can be disengaged, together with thecolumn side lower bracket 104, from the vehicle body side lower bracket103 to move frontward with respect to the vehicle body.

The tilting steering column apparatus is equipped with a steering column2 that supports the steering shaft 1 along its axis by means of bearings(not shown) and a clamp mechanism 3 attached to an expanded portion 13of the steering column 2, which will be described in detail later. Theclamp mechanism 3 comprises a tilt bracket 4, a tilt bolt 5, a nut 6, atilt lever 8 and paired fixed and movable cams 9 and 10. The steeringcolumn 2 is set at the center of the tilt bracket 4 that is fixed to thevehicle body.

The tilt bracket (the vehicle body side bracket) 4 is integrallycomposed of a pair of opposed flat plate portions 4 a, 4 b extending inthe axial direction on both sides of the steering column 2 and a vehiclebody mount portion 4 c that is fixed to the vehicle body and extendingin the transverse direction of the steering column 2. Alternatively, thepair of opposed flat portions 4 a, 4 b and the vehicle body mountportion 4 c may be separate members. The vehicle body side upper bracket(the tilt bracket) 4 is designed in such a way that upon secondarycollision, it moves frontward with respect to the vehicle body with thepair of opposed flat plate portions 4 a, 4 b being bent frontwardrelative to the vehicle body mount portion 4 c by an impact energyimparted on the tilt bolt 5 while generating a collapse load to absorbthe impact energy. Instead of the above-described structure, the upperbracket 4 may be separated into a vehicle body side bracket and a columnside bracket and a resin capsule or the like may be provided betweenthose brackets so that the column side bracket can be disengaged uponsecondary collision.

The tilt bolt 5 (a shaft) is inserted through a pair of long holes 5 a,5 b for allowing tilt adjustment formed on the opposed flat plateportions 4 a, 4 b of the tilt bracket 4, circular holes 16, 16 formed onthe expanded portion 13 of the steering column 2, the tilt lever 8, thefixed cam 9 and the movable cam 10. The nut 6 is screwed on a threadedportion at one end of the tilt bolt 5. The paired fixed cam 9 andmovable cam 10 are designed to engage the long hole 5 a for allowingtilt adjustment on the opposed flat plate portion 4 a of the tiltbracket 4 and the tilt lever 8 respectively.

As the tilt lever 8 is rotated, the movable cam 10 is rotated relativeto the fixed cam 9 that is always non-rotatable, whereby the tilt bolt 5(or the shaft) is pulled in its axial direction to change the distancebetween the pair of opposed flat plate portions 4 a and 4 b.

As shown in FIG. 2A, the steering column 2 has the expanded portion 13that was formed by expanding (or bulging) a portion of a tubularmaterial at an axially mid portion of the column by a hydraulic bulgeforming process.

As shown in FIGS. 2B and 2C, the expanded portion 13 has a pair of flatportions 14, opposed to the opposed flat plate portions 4 a and 4 brespectively, serving the clamp mechanism and transition portions 15through which the tubular material changes into the flat portions 14.

The flat portions 14 maintain a horizontal span S1, and the transitionportions 15 are formed with a horizontal span S2 that is substantiallyequal to the span S1. The span S1 refers to the span of the portions atwhich the circular holes 16 are formed.

As per the above, this embodiment is characterized by the conditionS1≈S2.

Letting D be the diameter of the steering column, although in theillustrated example (shown in FIGS. 2A to 2C) the condition S2≈D is met,this condition is not essential, but the apparatus may satisfy thecondition S2≠D.

On the flat portions 14, through holes such as circular holes 16 forexample, through which the tilt bolt 5 is inserted are formed byhydraulic bulge forming process.

The transition portions 15 formed with the same span as the flatportions 14 are located, with respect to the vertical direction, at acertain position between the circular holes 16 and the vehicle bodymount portion 4 c. Since the flat portions 14 and the transition portion15 are formed by expanding a portion of the same member, they have thesubstantially the same thickness. This is also the case with the otherembodiments that will be described later.

In this embodiment, as the tilt lever 8 is rotated in the tiltingoperation, the movable cam 10 engaging the tilt lever 8 is displacedrelative to the fixed cam 9. In that process, the tilt bolt (or theshaft) 5 is pulled in its axial direction, so that each of the opposedflat plate portions 4 a, 4 b of the tilt bracket 4 shifts inwardly toclamp the expanded portion 13 of the steering column 2 from the outside.

In this clamping process, the tilt bracket 4 and the steering column 2can be pressed together with a strong tightening force in the transitionportions 15 as well as in the flat portions 14 at which the clampmechanism is present. In other words, with the provision of the flatportions 14 and the transition portions 15 having substantially the samehorizontal span S1, S2, when the tilt bracket 4 is in contact with theflat portions 14 and the transition portions 15, these portions are inuniform, close contact with the opposed flat plate portions 4 a and 4 b,so that a uniform tightening force is produced. Consequently, the tiltbracket 4 and the steering column 2 can be pressed together with astrong tightening force also in transition portions 15 as well as in theflat portions 14.

The expanded portion 13 in this embodiment is formed by expanding aportion of the material of the steering column 2, and a large sizedistance bracket extending beyond the center of the steering column 2 isnot used. Therefore, the weight of the steering column apparatus is notincreased. Furthermore, since a special member such as a spacer made ofa resin is not used, the structure of the clamp mechanism can be madesimple and the steering column apparatus can be manufactured at low costwith a decreased number of parts.

As per the above, in this embodiment, when the steering column 2 is heldbetween the opposed flat plate portions 4 a and 4 b of the tilt bracket4, the steering column 2 can be brought into pressure contact with theopposed flat plate portions 4 a and 4 b with a strong tightening forcealso in the transition portions 15 as well as in the flat portions 14.Thus, it is possible to improve rigidity in supporting the steeringcolumn 2 without providing a special member.

As described before, this embodiment is characterized by the conditionS1≈S2. Although the condition S2≈D (D is the outer diameter of thesteering column) is met in the illustrated example (FIGS. 2A to 2C),this condition is not essential, but the apparatus may satisfy thecondition S2≠D.

Second Embodiment Telescopic Type

In the following, the second embodiment of the present invention will bedescribed with reference to FIGS. 3A and 3B. FIGS. 3A and 3B show asteering column apparatus according to the second embodiment of thepresent invention. FIG. 3A is a side view of the steering column andFIG. 3B is a cross sectional view of the steering column.

The steering column of the second embodiment is telescopic type unlikethe above-described first embodiment, but the structure shown in FIGS.1A and 1B (i.e. the structure and positional relationship of the clampmechanism 3, the vehicle body side bracket 4 and the shaft 5 etc.) alsoapplies to the steering column of the second embodiment.

The steering column shown in FIGS. 3A and 3B can be used in a telescopicapparatus or a tilting, telescopic steering apparatus.

As shown in FIG. 3A and 3B, the steering column 2 has an expandedportion 17 formed by expanding (or bulging) a portion of a tubularmaterial at an axially mid portion of the column by a hydraulic bulgeforming process.

The expanded portion 17 has a pair of flat portions 18 respectivelyopposed to the opposed flat plate portions 4 a and 4 b shown in FIGS. 1Aand 1B and transition portions 19 through which the tubular materialchanges into the flat portions 18.

The flat portions 18 maintain a horizontal span S1, and the transitionportions 19 are formed with a horizontal span S2 that is substantiallyequal to the span S1. The span S1 refers to the span of the portion atwhich long holes 20 are formed.

As per the above, this embodiment is characterized by the conditionS1≈S2.

Letting D be the diameter of the steering column, although in theillustrated example (shown in FIGS. 2A to 2C) the condition S2≈D is met,this condition is not essential, but the apparatus may satisfy thecondition S2≠D.

On the flat portions 18, through holes such as long holes 20 forexample, through which a tightening bolt (not shown) is inserted areformed.

The transition portions 19 formed with the same span as the flatportions 18 are located, with respect to the vertical direction, at acertain position between the long holes 20 and the vehicle body mountportion 4 c.

In this embodiment, pressure contact with the tilt bracket 4 can beattained also in the transition portions 19 as well as in the flatportions 18. In other words, with the provision of the flat portions 18and the transition portions 19 having substantially the same horizontalspan S1, S2, when the opposed flat plate portions 4 a, 4 b are incontact with the flat portions 18 and the transition portions 19, theseportions are in uniform, close contact with the opposed flat plateportions 4 a and 4 b, so that a uniform tightening force is produced.Consequently, pressure contact with the opposed flat plate portions 4 a,4 b with a strong tightening force is realized also in transitionportions 19 as well as in the flat portions 18.

In this embodiment, when the telescopic steering column 2 is held by thebracket, the steering column 2 can be brought into pressure contact withthe opposed flat plate portions 4 a and 4 b with a strong tighteningforce also in the transition portions 19 as well as in the flat portions18. Thus, it is possible to improve rigidity in supporting the steeringcolumn 2 without providing a special member.

As described before, this embodiment is characterized by the conditionS1≈S2. Although the condition S2≈D (D is the outer diameter of thesteering column) is met in the illustrated example (FIGS. 2A to 2C),this condition is not essential, but the apparatus may satisfy thecondition S2≠D.

Third Embodiment Tilting Type

In the following, the third embodiment of the present invention will bedescribed with reference to FIGS. 4A and 4B. FIGS. 4A and 4B show asteering column according to the third embodiment of the presentinvention. FIG. 4A is a side view of the steering column and FIG. 4B isa cross sectional view of the steering column.

The steering column of the third embodiment is of a tilting type as withthe above-described first embodiment, and the structure shown in FIGS.1A and 1B (i.e. the structure and the positional relationship of theclamp mechanism 3, the vehicle body side bracket 4 and the shaft 5 etc.)also applies to the steering column of the third embodiment.

The steering column shown in FIGS. 4A and 4B can be used in a tiltingsteering apparatus.

As shown in FIGS. 4A and 4B, the tilting steering column 2 has anexpanded portion 21 that was formed by expanding (or bulging) a portionof a tubular material at an axially mid portion of the column by ahydraulic bulge forming process.

The expanded portion 21 has a pair of flat portions 22 respectivelyopposed to the opposed flat plate portions 4 a and 4 b shown in FIG. 1Band a pair of transition portions 23.

The transition portions 23 maintain a horizontal span S4 substantiallyequal to the diameter D of the steering column 2, and the flat portions22 are formed with a horizontal span S3 that is slightly smaller thanthe span S4. The span S3 refers to the span of the portions at whichcircular holes 16 are formed.

In spite of the above statement that the diameter D and the span S4 aresubstantially equal to each other, this condition is not essential, butthe apparatus may satisfy the condition D<S4 or D>S4.

In connection with the above, S3 and S4 are connected by a slope, namelythey are on the same plane.

In the flat portions 22, the circular holes 16 through which atightening bolt (not shown) is inserted are formed.

The transition portions 23 formed with the span S4 different from thatof the flat portions 22 are located, with respect to the verticaldirection, at a certain position between the circular holes 16 and thevehicle body mount portion 4 c.

In this embodiment, more reliable pressure contact with the opposed flatplate portions 4 a and 4 b is realized especially by the transitionportions 23 having the span S4 larger than the span S3 of the flatportions 22. Accordingly, even if an offset is present between thecenter of the clamp mechanism 3 and the transition portions 23, thetightening force of the clamp mechanism 3 can be exerted on both theflat portions 22 and the transition portions 23 uniformly.

As per the above, when the steering column 2 is held between the opposedflat plate portions 4 a and 4 b, the members can be pressed together bythe transition portions 23 with a strong tightening force. Consequently,a high rigidity can be attained in supporting the steering column 2.

In this embodiment, when the steering column 2 is held between theopposed flat plate portions 4 a and 4 b, the steering column 2 can bebrought into pressure contact with the opposed flat plate portions 4 aand 4 b with a strong tightening force in the transition portions 23having the span S4 larger than the span S3 of the flat portions 22.Thus, it is possible to enhance rigidity in supporting the steeringcolumn 2 without providing a special member.

Although it was described in the above that the diameter D and the spanS4 are substantially equal to each other, this condition is notessential, but the apparatus may satisfy the condition D<S4 or D>S4.

Fourth Embodiment Tilting Type

In the following, the fourth embodiment of the present invention will bedescribed with reference to FIGS. 5A and 5B. FIGS. 5A and 5B show asteering column according to the fourth embodiment of the presentinvention. FIG. 5A is a side view of the steering column and FIG. 5B isa cross sectional view of the steering column.

The steering column of the fourth embodiment is of a tilting type aswith the above-described first embodiment, and the structure shown inFIGS. 1A and 1B (i.e. the structure and the positional relationship ofthe clamp mechanism 3, the vehicle body side bracket 4 and the shaft 5etc.) also applies to the steering column of the fourth embodiment.

The steering column shown in FIGS. 5A and 5B can be used in a tiltingsteering apparatus.

The tilting steering column 2 has paired first and second expandedportions 24 a and 24 b formed by expanding (or bulging) a portion oftubular material upwardly and downwardly at an axially mid portion ofthe column by a hydraulic bulge forming process.

The first expanded portion 24 a has a pair of first flat portions 25, 25opposed to the opposed flat plate portions 4 a, 4 b shown in FIGS. 1Aand 1B. The second expanded portion 24 b has a pair of second flatportions 26, 26 located between circular holes 16 and the vehicle bodymount portion 4 c.

The first flat portions 25 are formed with a horizontal span S3 and thesecond flat portions 26 are formed with a horizontal span S4 equal to orslightly larger than the span S3. The span S3 refers to the span of theportions at which the circular holes 16 are formed.

As per the above, this embodiment is characterized by the conditionS4≧S3.

In addition, in this embodiment, either S3 or S4 is equal to D. However,this condition is not essential, but the apparatus may satisfy thecondition (S3, S4)>D or the condition (S3, S4)<D.

Furthermore, the first flat portion 25 and the second flat portion 26may be coplanar.

In this embodiment, more reliable pressure contact with the opposed flatplate portions 4 a and 4 b is realized by the second flat portions 26having the span S4 equal to or larger than the span S3 of the first flatportions 25. Accordingly, even if offset is present between the centerof the clamp mechanism and the second flat portions 26, the tighteningforce of the clamp mechanism can be exerted on both the first flatportions 25 and the second flat portions 26 uniformly.

Thus, when the steering column 2 is held between the opposed flat plateportions 4 a and 4 b, the members can be pressed together in the secondflat portions 26 with a strong tightening force. Consequently, a highrigidity can be attained in supporting the steering column.

Modification of the Fourth Embodiment

The above-described embodiment may be modified in such a way that thefirst flat portions 25 and the second flat portions 26 (located betweenthe circular holes 16 and the vehicle body mount portion 4 c) havehorizontal spans S3 and S4 significantly larger than the outer diameterD of the steering column 2, as shown in FIGS. 6A and 6B.

The first flat portions 25 are formed with a horizontal span S3 and thesecond flat portions 26 are formed with a horizontal span S4 equal to orslightly larger than the span S4. The span S3 refers to the span of theportions at which the circular holes 16 are formed.

As per the above, this modification is characterized by the conditionS4≧S3.

In addition, the condition S4>S5 and the condition S3>S5 are met in thismodification.

Furthermore, in this modification, S5 is equal to D. However, thiscondition is not essential, but the condition S5>D or S5<D may be met.

The first flat portion 25 and the second flat portion 26 may becoplanar.

In this embodiment, when the tilting steering column 2 is held betweenthe opposed flat plate portions 4 a and 4 b, more reliable pressurecontact with the opposed flat plate portions 4 a, 4 b is realized in thesecond flat portions 26 having the span S4 equal to or larger than thespan S3 of the first flat portions 25. Therefore, it is possible toenhance rigidity in supporting the steering column 2 without providing aspecial member.

Fifth Embodiment Tilt Telescopic Type

FIG. 7 is a side view showing a tilting telescopic steering apparatusfor a vehicle according to the fifth embodiment of the presentinvention. FIG. 8 is a cross sectional view taken along line A-A in FIG.7, showing only the expanded portion of the steering column. FIG. 9A isa cross sectional view taken along line A-A in FIG. 7, showing a statein which clamping of the column is released. FIG. 9B is a similar crosssectional showing a state in which the column is clamped.

In the tilting telescopic steering apparatus affording to the fifthembodiment of the present invention shown in FIGS. 7, 8, 9A and 9B, asteering shaft 32 is rotatably supported on a steering column 31, and asteering wheel 33 is attached on the rear end (with respect to thevehicle body) of the steering shaft 32.

The central portion of the steering column 31 is supported on a vehiclebody mount upper bracket 35 in a swingable way. The vehicle body mountupper bracket 35 is fixed to the vehicle body. The vehicle body mountupper bracket 35 has a pair of horizontal portions 35 a, 35 a (vehiclebody mount portions) extending transversely to the steering column 31and a pair of opposed flat plate portions 35 b, 35 b that are integralwith the pair of horizontal portions 35 a, 35 a and extended downwardfrom them to extend in the axial direction on both sides of the steeringcolumn 31. On the pair of opposed flat plate portions 35 b, 35 b, a pairof long holes 36, 36 for allowing tilt adjustment are formed.

The pair of horizontal portions 35 a, 35 a and the pair of opposed flatplate portions 35 b, 35 b may be formed as separate members.

An expanded portion 37 is formed at the axially central portion of thesteering column 31 by a hydroforming process. In the expanded portion 37integrally formed on the steering column 31, both side portions 37 a, 37a that are in contact with the opposed flat plate portions 35 b, 35 b ofthe vehicle body mount upper bracket 35 respectively so as to besupported by the vehicle body mount upper bracket 35 are integrallyformed. On both the side portions 37 a, 37 a, a pair of long holes 38,38 for allowing tilt adjustment are formed. A tightening bolt 39provided with a clamp mechanism 48 is inserted through the pair of tiltadjustment long holes 36, 36 and the pair of column position adjustmentlong holes 38, 38. An operation lever 40 is rotatably mounted on thetightening bolt 39. The clamp mechanism 48 may be a well known mechanismincluding a cam mechanism.

The lower, front (with respect to the vehicle body) portion of thesteering column 31 is supported by a vehicle body mount lower bracket 34in a swingable way. The vehicle body mount lower bracket 34 is fixed tothe vehicle body. The vehicle body mount lower bracket 34 has a pair ofhorizontal portions 34 a, 34 a extending transversely to the steeringcolumn 31 and a pair of opposed flat plate portions 34 b, 34 b that areintegral with the pair of horizontal portions 34 a, 34 a and extendeddownward from them to extend in the axial direction on both sides of thesteering column 31. On the pair of opposed flat plate portions 34 b, 34b, a pair of bracket supporting holes 34 c, 34 c are formed.

At the lower, front (with respect to the vehicle body) end of thesteering column 31, a support bracket portion 44 is attached by, forexample, welding. The support bracket portion 44 has both side portions44 a, 44 a that are in contact with the opposed flat plate portions 34b, 34 b of the vehicle body mount lower bracket 34 respectively so as tobe supported. A pair of long holes 46, 46 for allowing column positionadjustment are formed on both the side portions 44 a, 44 a. The supportbracket portion 44 is supported by the vehicle body mount bracket 34 ina slidable and rotatable manner by means of the long holes 46, 46 andthe bracket supporting holes 34 c, 34 c and hinge pins 45, 45. Thetilting telescopic steering apparatus has the above-described structure.

The support bracket portion 44 is formed integrally with the steeringcolumn 31 by a hydroforming process that will be described later.Alternatively, the supporting bracket portion 44 and the steering column31 may be formed as separate members.

In the tilting telescopic steering apparatus having the above-describedstructure, when the tilt and telescopic position is to be fixed afteradjustment (in the column position adjustment), the operation lever 40is rotated in the tightening direction. By that operation, the distancebetween the head of the tightening bolt 39 and an adjustment nut 41 isdecreased, so that the pair of opposed flat plate portions 35 b, 35 b ofthe vehicle body mount upper bracket 35 are securely pressed againstboth the side portions 37 a, 37 a of the expanded portion 37 of thesteering column 31. Thus, the tilt and telescopic adjusted position ofthe steering column 31 is fixed.

On the other hand, when the tilt and telescopic position is to beadjusted, the operation lever is rotated in the releasing direction. Bythat operation, the distance between the head of the tightening bolt 39and the adjustment nut 41 is increased, so that secure pressure contactof the pair of opposed flat plate portions 35 b, 35 b of the vehiclebody mount upper bracket 35 and both the side portions 37 a, 37 a of theexpanded portion 37 of the steering column 31 is released. Thus,adjustment of the tilt and telescopic position of the steering column 31is allowed. With the above-described process, the steering column 31 canbe adjusted to a desired tilt and telescopic position.

As shown in FIG. 8, in this embodiment, a single blank in the form of asteel tube material is formed into a steering column 31 having anintegral expanded portion 37 by a hydroforming process. On both the sideportions 37 a, 37 a of the expanded portion 37, the pair of long holes38, 38 for allowing column position adjustment through which thetightening bolt 39 provided with the clamp mechanism 48 is inserted areformed. The clamp mechanism 48 may include the cam mechanism used in thefirst embodiment.

In this embodiment, both the side portions 37 a, 37 a of the expandedportion 37 are slanted in such a way that the distance (Dd) therebetweenat the lower end is slightly smaller than the distance (Du) therebetweenat the upper end. The distance Du is the span of the portions at whichthe long holes 38 for allowing column position adjustment are formed.

Therefore, the contact area of those members can be increased and theforce for securing the steering column 31 on the vehicle body can beincreased. This leads to improvement in rigidity against vibration andan increase in the securing force upon collision.

The hydroforming is a method of placing a thin-walled steel pipe in ametallic mold and filling the interior of the steel pipe withpressurized water or pressurized oil to expand the steel pipe to shapeit into a desired form or simply filling the interior of the pipe withrubber or the like to expand it. This method is advantageous over theprocess of forming a member having a closed cross sectional structure bywelding after press molding, since the product will not be much deformedby heat thanks to the lack of a welded portion and therefore processingor manufacturing cost reduction and weight reduction can be expected.

As per the above, in this embodiment, since the expanded portion 7 has aclosed cross sectional structure integral with the steering column 31,the steering column 31 itself can be made rigid and the force forsecuring the steering column 31 to the vehicle body can be made strong.In addition, the manufacturing cost (including the material cost,processing cost and assembling cost) and the weight can be reduced.

Although the description of this embodiment of the present invention hasbeen made with reference to the case in which the steering column isproduced by a hydroforming process, the production method is not limitedto the hydroforming process, but the steering column may be formed by arubber bulge forming process, an explosion bulge forming process or apressing process.

In this embodiment, the condition Dd<Du is met. In addition, letting Dbe the diameter of the steering column 2 (not shown), the condition Du≈Dis met. However, this condition is not essential, but the condition Du≠Dmay be met.

Sixth Embodiment Tilting Type

FIG. 10A is an enlarged side view showing a portion of interest of asteering column of a tilting steering apparatus for a vehicle accordingto the sixth embodiment of the present invention. FIG. 10B is a crosssectional view taken along line b-b in FIG. 10A.

The steering column in the sixth embodiment is of a tilting type as withthe above-described first embodiment, and the structure shown in FIGS.1A and 1B (i.e. the structure and positional relationship of the clampmechanism 3, the vehicle body side bracket 4, and the shaft 5 etc.) alsoapplies to the steering column according to the sixth embodiment.

The steering column shown in FIGS. 10A and 10B can be used in a tiltingsteering apparatus.

The tilting steering column 51 has paired first and second expandedportions 52 a and 52 b formed by expanding (or bulging) a portion oftubular material upwardly and downwardly at a certain position in theaxial direction of the column by a hydraulic bulge forming process.

The first expanded portion 52 a has a pair of first flat portions 53, 53opposed to the opposed flat plate portions 4 a, 4 b shown in FIGS. 1Aand 1B. The second expanded portion 52 b has a pair of second flatportions 54, 54 located between circular holes 55 and the vehicle bodymount portion 4 c.

The first flat portions 53 have a horizontal span X that is smaller thanthe horizontal span W of transition portions between the first andsecond flat portions 53 and 54. In other words, the condition W≧X ismet. The span X refers to the span of the portions at which circularholes 55 are formed.

The second flat portions 54 have a horizontal span Y that is smallerthan the span W. In other words, the condition W≧Y is met. The span Yrefers to the span of the upper portions of the second flat portions 54.

Whether Y>X or Y<X does not matter, so long as the conditions W≧X andW≧Y are met.

In addition, no conditions are placed on the relationship between X andY and the relationship between W and D, so long as the conditions W≧Xand W≧Y are met.

As per the above, since those portions are so formed as to satisfy theconditions W≧X and W≧Y, when the steering column 2 is held between theopposed flat plate portions 4 a, 4 b, the members can be pressedtogether in the first and second flat portions 53 and 54 with a strongtightening force, as is the case with the above-described embodiments.Consequently, a high rigidity can be attained in supporting the steeringcolumn 2.

Seventh Embodiment Tilting Type

FIG. 11 is a transverse cross sectional view of a tilting steeringapparatus for a vehicle according to the seventh embodiment of thepresent invention.

FIG. 12A is an enlarged side view showing a portion of interest of thesteering column of the tilting steering apparatus for a vehicleaccording to the seventh embodiment of the present invention. FIG. 12Bis a cross sectional view taken along line b-b in FIG. 12A.

As shown in FIG. 11, the tilting steering column apparatus has asteering column 62 for supporting a steering shaft 61 along its axis viaa bearing (not shown) and a clamp mechanism 63 attached to an expandedportion 73 of the steering column 62.

The clamp mechanism 63 comprises a tilt bracket 64, a tilt bolt (ashaft) 65, a nut 66, a tilt lever 68 and paired fixed and movable cams69 and 70.

The tilt bracket 64 (i.e. the vehicle body side bracket) is integrallycomposed of a pair of opposed flat plate portions 64 a, 64 b extendingaxially on both sides of the steering column and a vehicle body mountportion 64 c extending transversely to the steering column 61.Alternatively, the pair of opposed flat plate portions 64 a, 64 b andthe vehicle body mount portion 64 c may be formed as separate members.On the pair of opposed flat plate portions 64 a and 64 b, long holes 79a and 79 b for allowing tilt adjustment are formed respectively.

In this embodiment, the vehicle body mount portion 64 c is disposedbelow the center axis of the steering column 62, and the pair of opposedflat plate portions 64 a, 64 b extend substantially upwardly from thevehicle body mount portion 64 c.

The tilt bolt (shaft) 65 is inserted through the opposed flat plateportions 64 a, 64 b of the tilt bracket 64, an expanded portion of thesteering column 62, the tilt lever 68, the fixed cam 69 and the movablecam 70. The nut 66 is screwed on a threaded portion at one end of thetilt bolt 65. The paired fixed and movable cams 69 and 70 engage theflat plate portion 64 a and the tilt lever 68 respectively.

Thus, as the tilt lever 68 is rotated, the movable cam 70 rotatesrelative to the fixed cam 69, which is always non-rotatable, whereby thetilt bolt (shaft) 65 is pulled in its axial direction, so that thedistance between the pair of opposed flat plate portions 64 a and 64 bis changed.

As shown in FIGS. 12A and 12B, the steering column 62 has an expandedportion 73 formed by expanding (or bulging) a portion of a tubularmaterial at an axially mid portion of the column by a hydraulic bulgeforming process.

The expanded portion 73 has a pair of flat portions 74 opposed to theopposed flat plate portions 64 a and 64 b respectively for serving theclamp mechanism 63 and transition portions 75 through which the tubularmaterial changes into the flat portions 74.

The flat portions 74 have a span Z1 that is smaller than the span Z2 ofthe transition portions 75. In other words the condition Z2>Z1 is met.The span Z1 refers to the span of the portions at which circular holes76 are formed.

Although the relationship between Z2 and D is Z2≈D, Z2 and D may be ofany relationship.

On the flat portions 74, through holes, or the circular holes 76 forexample, through which the tilt bolt (or the shaft) is inserted areformed by hydraulic bulge forming process.

In this embodiment, as the tilt lever 68 is rotated in the tiltingoperation, the movable cam 70 engaging the tilt lever 68 is displacedrelative to the fixed cam 69. In that process, the tilt bolt (shaft) 65is pulled in its axial direction, so that each of the opposed flat plateportions 64 a, 64 b of the tilt bracket 64 shifts inwardly to clamp theexpanded portion 73 of the steering column 62 from the outside.

In this clamping process, the tilt bracket 64 and the steering column 62can be pressed together with a strong tightening force in the transitionportions 75 as well as in the flat portions 74 at which the clampmechanism is present.

As per the above, in this embodiment, when the steering column 62 isheld between the opposed flat plate portions 64 a and 64 b of the tiltbracket 64, the steering column 62 can be brought into pressure contactwith the opposed flat plate portions 64 a and 64 b with a strongtightening force also in the transition portions 75 as well as in theflat portions 74. Thus, it is possible to improve rigidity in supportingthe steering column 62 without providing a special member.

The present invention is not limited to the embodiments described above,but various modifications can be made. For example, the positionadjustable steering column apparatus for a vehicle according to thepresent invention may be any of the tilting, telescopic andtilting-telescopic types.

As has been described in the foregoing, according to the presentinvention, it is possible to enhance rigidity in supporting the steeringcolumn without adding a special member. In addition, it is possible toprovide a steering apparatus for a vehicle in which the force forsecuring the steering column on the vehicle body is enhanced, byincreasing the contact area between an expanded portion integrallyformed on the steering column and opposed flat plate portions of avehicle body mount bracket.

1. A position adjustable steering apparatus for a vehicle comprising: avehicle body side bracket having a vehicle body mount portion to bemounted on a vehicle body and paired left and right opposed flat plateportions extending in the substantially vertical direction; a steeringcolumn for rotatably supporting a steering shaft, the steering columnhaving an expanded portion, formed by expanding a portion of a tubularmaterial, that is to be in pressure contact with the pair of opposedflat plate portions of said vehicle body side bracket; a shaft insertedthrough said pair of opposed flat plate portions and said expandedportion; and an adjustment mechanism that acts on said shaft as anoperation lever is rotated, for adjusting the distance between said pairof opposed flat plate portions, wherein said steering column has aportion that is present in an area extending from said shaft up to atleast said vehicle body mount portion and has a width substantiallyequal to the width of a penetrated portion of said expanded portion atwhich said shaft is inserted through.
 2. A position adjustable steeringapparatus for a vehicle comprising: a vehicle body side bracket having avehicle body mount portion to be mounted on a vehicle body and pairedleft and right opposed flat plate portions extending in thesubstantially vertical direction; a steering column for rotatablysupporting a steering shaft, the steering column having an expandedportion, formed by expanding a portion of a tubular material, that is tobe in pressure contact with the pair of opposed flat plate portions ofsaid vehicle body side bracket; a shaft inserted through said pair ofopposed flat plate portions and said expanded portion; and an adjustmentmechanism that acts on said shaft as an operation lever is rotated, foradjusting the distance between said pair of opposed flat plate portions,wherein said steering column has a portion that is present in an areaextending from said shaft up to at least said vehicle body mount portionand has a width larger than the width of a penetrated portion of saidexpanded portion at which said shaft is inserted through.
 3. A positionadjustable steering apparatus for a vehicle comprising: a vehicle bodyside bracket having a vehicle body mount portion to be mounted on avehicle body and paired left and right opposed flat plate portionsextending in the substantially vertical direction; a steering column forrotatably supporting a steering shaft, the steering column having afirst expanded portion, formed by expanding a portion of a tubularmaterial, that is to be in pressure contact with the pair of opposedflat plate portions of said vehicle body side bracket; a shaft insertedthrough said pair of opposed flat plate portions and said first expandedportion; and an adjustment mechanism that acts on said shaft as anoperation lever is rotated, for adjusting the distance between said pairof opposed flat plate portions, wherein said steering column has asecond expanded portion expanded from a substantially center portionthereof at said vehicle body mount portion side, and said steeringcolumn has a portion that is present in an area extending from saidshaft up to at least said vehicle body mount portion and has a widthsubstantially equal to the width of a penetrated portion of said firstexpanded portion at which said shaft is inserted through and the widthof said second expanded portion.
 4. A position adjustable steeringapparatus for a vehicle comprising: a vehicle body side bracket having avehicle body mount portion to be mounted on a vehicle body and pairedleft and right opposed flat plate portions extending in thesubstantially vertical direction; a steering column for rotatablysupporting a steering shaft, the steering column having a first expandedportion, formed by expanding a portion of a tubular material, that is tobe in pressure contact with the pair of opposed flat plate portions ofsaid vehicle body side bracket; a shaft inserted through said pair ofopposed flat plate portions and said first expanded portion; and anadjustment mechanism that acts on said shaft as an operation lever isrotated, for adjusting the distance between said pair of opposed flatplate portions, wherein said steering column has a second expandedportion expanded from a substantially center portion thereof at saidvehicle body mount portion side, and said steering column has a portionthat is present in an area extending from said shaft up to at least saidvehicle body mount portion and has a width larger than the width of apenetrated portion of said first expanded portion at which said shaft isinserted through and the width of said second expanded portion.